The present invention generally relates to the field of stabilized, equipment transporting devices, and more particularly, to a simple and efficient apparatus for the high-speed transport of lightweight cameras or other equipment which may be orientation-sensitive and/or stability-sensitive so that the equipment is isolated from unwanted motions. Although the following discussion will proceed in the context of motion picture (primarily video) applications for purposes of convenience in description, it is to be understood that the improvements which are described will find utility in connection with any of a variety of possible applications.
Since the beginning of motion picture photography, when it became desirable to transport cameras in a stable manner, so-called "camera dollies" have been used to ameliorate the adverse effects of motion in the camera. Such dollies tend to be simple wheeled vehicles, without any suspension or other means for isolating the camera from unwanted movements of the dolly. What is more, such dollies are quite cumbersome in use since unless the terrain consists of near perfect planar flooring, the dolly must ride on a system of rails for leveling irregularities in the supporting surface. Such rail systems must in turn be laboriously leveled to achieve their intended result.
Such shortcomings have led to the invention of the "Steadicam.RTM." and "Skycam.RTM." camera transporting systems. The "Steadicam.RTM." camera transporting system is described in U.S. Pat. Nos. RE 32,213; 4,156,512; 4,208,028; 4,394,075; and 4,474,439, and has become an industry standard for stabilizing ambulatory, hand-held cameras. The "Skycam.RTM." camera transporting system is described in U.S. Pat. Nos. 4,533,955; 4,625,938; and 4,710,819, and provides a stabilized aerial camera transport to, in essence, "fly" a suspended camera over an area such as an arena or auditorium. Both of these devices avoid the need for rails, and operate conveniently and smoothly over rough terrain.
However, the underlying difficulties with rail systems remained unsolved and such problems have become aggravated as the required speed of transport (for camera systems) has increased responsive to the demands of the industry.
Known dolly and rail systems generally employ two rails for the dolly. So-called "monorail" systems have also been developed, employing a single rail structure having at least two surfaces (e.g., an I-beam) for receiving the dolly's wheels. In each case, the dolly is suitably referenced to the upright, level position which is needed for the equipment it supports. The difficulty is that the two rails, or the two surfaces of a monorail, must not only be laid straight and true along the path of the dolly's progress, but also must be carefully leveled in reference to one another. Otherwise, the dolly will tend to lurch (transverse lateral and rolling movements) down the rails (or rail) of the system. Even with the best of care, such leveling operations can only be as accurate as the equipment (e.g., the bubble level or digital level sensing device) employed. As the speed of the dolly's progress increases, virtually any irregularities can cause increasing vibration in the camera sequences obtained (i.e., the "shot").
As the need for stable, high-speed traveling shots increased over the years, a variety of isolated, mass/gyro-stabilized camera systems (housings) were developed which could be transported by other, essentially unstable vehicles (including helicopters and camera cars) at practical speeds. In an effort to provide a stabilized camera transport system smaller than a camera car, and adapted for sports coverage, a device (a vehicle known as "RailCam.TM.") was developed to transport such stabilized gyro-cameras using an electrically powered, unstabilized dolly running on a rail system. Although this device has been used to make exciting traveling shots of runners and ice-skaters, it is expensive, labor intensive, large and power demanding. As a result, the device can only meet the needs of large, well-funded sporting events.
At the same time, video cameras have continued to reduce in size, and the need for a small, stable, ultra-light, self-propelled camera transport system has become more acute. The above-described "RailCam.TM." device has been unable to meet limited budgeting requirements, yet the need to enhance viewer excitement by obtaining moving camera shots in an increasingly diverse spectrum of events, including sports, music and entertainment television, has continued to increase. In an effort to satisfy these ever-increasing needs, so-called "point-of-view" cameras have proliferated in an effort to place viewers in the midst of the action. Particularly for sporting events, such miniature cameras have been inconspicuously placed on race-cars, and on the helmets of football players, but the stability of the shots obtained using such equipment is limited to the inherent stability of the carrier (i.e., the race-car or football player).
Despite all efforts directed at this problem, there remains no comparable, ultra-small tracking camera system of a size and weight appropriate for use with the miniature high-quality video cameras which are currently available. It therefore remained to develop such a system, capable of delivering a slim, ultra-light, railed "footprint", and capable of rapid, versatile and silent deployment close to the action to be shot, yet which is stabilized to a sufficient degree to provide "broadcast-quality" images during such high-speed tracking applications.